(a) Field of the Invention
The present invention relates to a method for pelleting spherical fine particles of sodium nitrate.
(b) Description of the Related Art
General industrial sodium nitrate (in compliance with the national standard GB/T4553) is an irregular aspherical crystalline powder with high water content, easy absorption of moisture to form cakes, poor disperability, and inconvenience to use. To overcome the aforementioned problems of existing sodium nitrate particles, CN1205125C provides a method of manufacturing sodium nitrate particles, wherein industrial sodium nitrate is melted and pumped in a the high-level tank, and then sprayed out from a nozzle of a low-level pelleting tower, and a dispersion device is provided to shake the melted sodium nitrate up and down, and back and forth to form uniform droplets, and the droplets falling down in the pelleting tower are contacted with an upstream of air and cooled to form particles to achieve the effects of reducing the water content and enhancing the dispersability.
However, the aforementioned manufacturing method still has the following deficiencies:
1. The spherical or oval droplets sprayed out from the nozzle are deformed naturally during the falling process, so that various different shaped particles are obtained after the cooling process, and the roundness of the particles with an irregular shape fails to reach the level of 0.8, and the number of spherical particle is far less than 80%, and the dispersability requires improvements;
2. The droplets of sodium nitrate come with large specific surface area and strong moisture absorption, and the method using room-temperature air with larger water content to cool the droplets of sodium nitrate solution leads to the production of heavy sodium nitrate particles with a large quantity of absorbed water;
3. The use of reciprocating vibration technology can disperse the droplets of sodium nitrate to form particles with a diameter within a range of 0.3˜3 mm, and a very low yield rate of the particles having a size within a range of 0.5 mm˜1 mm, and the diameter of the particles of the product cannot be controlled below 0.5 mm; and
4. A continual production cannot be achieved.